An Air‐Stable High‐Nickel Cathode with Reinforced Electrochemical Performance Enabled by Convertible Amorphous Li<sub>2</sub>CO<sub>3</sub> Modification
Hang Sheng, Xin‐Hai Meng, Dong‐Dong Xiao, Min Fan, Wan‐Ping Chen, Jing Wan, Jilin Tang, Yu‐Gang Zou, Fuyi Wang, Rui Wen, Ji‐Lei Shi, Yu‐Guo Guo
Abstract
Abstract High‐nickel (Ni ≥ 90%) cathodes with high specific capacity hold great potential for next‐generation lithium‐ion batteries (LIBs). However, their practical application is restricted by the high interfacial reactivity under continuous air erosion and electrolyte assault. Herein, a stable high‐nickel cathode is rationally designed via in situ induction of a dense amorphous Li 2 CO 3 on the particle surface by a preemptive atmosphere control. Among the residual lithium compounds, Li 2 CO 3 is the most thermodynamically stable one, so a dense Li 2 CO 3 coating layer can serve as a physical protection layer to isolate the cathode from contact with moist air. Furthermore, amorphous Li 2 CO 3 can be transformed into a robust F‐rich cathode electrolyte interphase (CEI) during cycling, which reinforces the cathode's interfacial stability and improves the electrochemical performance. The assembled coin cell with this modified cathode delivers a high discharge capacity of 232.4 mAh g –1 with a superior initial Coulombic efficiency (CE) of 95.1%, and considerable capacity retention of 90.4% after 100 cycles. Furthermore, no slurry gelation occurs during the large‐scale electrode fabrication process. This work opens a valuable perspective on the evolution of amorphous Li 2 CO 3 in LIBs and provides guidance on protecting unstable high‐capacity cathodes for energy‐storage devices.